Mounting block for circuit breaker



W. H. EDMUNDS MOUNTING BLOCK FOR CIRCUIT BREAKER Sept. 3, 1957 3 Sheets-Sheet 1 Filed Dec. 9, 1955 IN VEN TOR. Mi 4M flfllaLp [amwvos P 1957 w. H. EDMUNDS 2,805,294

MOUNTING BLOCK FOR CIRCUIT BREAKER Filed Dec. 9, 1955 3 Sheets-Sheet 5 IN VEN TOR. (011.1140; lq flxaza EpI/wvos United States Patent MOUNTING BLOCK FOR CIRCUIT BREAKER William Harold Edmunds, Havertown, Pa., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Application December 9, 1955, Serial No. 552,079

7 Claims. (Cl. 200-51) My invention relates to a circuit interrupter mounting means so that the circuit breaker can be selectively positioned to either energize or de-energize a circuit.

In many industrial applications wherein circuit protective means are provided for both automatic and manual de-energization of the electrical circuit, it is necessary to provide positive means to insure that the circuit protective device is in a position which maintains the circuit in a de-energized condition. That is, in the event of repair or inspection of the electrical line by a maintenance man, it is desirable to have positive protective means to insure that the circuit on which the operator is to work is, in fact, de-energized.

Thus, in many installations, when the maintenance man is to perform work on the electrical line, he must know that in fact, the circuit is tie-energized.

Many methods have heretofore been proposed and used but have been unsatisfactory since either they do not have universal application and/or are not foolproof constructions. Thus, for example, in some installations wherein a fuse and switch combination is used in the circuit, the switch blade is moved to the fully open position thereby indicating that the circuit is de-energized. However, in some cases, even though the switch contact blade is in re open position, the circuit is not completely de-energized due to the fact that the insulating material may be carbonized to a point that leakage current may be present across the surface so that there will be a false indication of de-energization of the circuit.

In order to overcome this disadvantage, many installations have utilized circuit breakers wherein the movable contacts can be manually moved from the on to the OH position. However, in most of these installations, the operating components are contained within a housing such as a molded case and thus, the only visual indication that the circuit breaker is open is the fact that the operating handle is in the off position. However, this has not been completely satisfactory since there have been some situations in which the cooperating contacts have welded together and the handle in the off position has given a false sense of security to the maintenance man since the line is still energized even though the visual indicator, that is, the circuit breaker handle, is in the off position.

In one prior art arrangement designed to overcome this disadvantage, the housing was cut away in the area adjacent the cooperating contacts. However, this has proved to be unsatisfactory in view of the flash and flame which emanates from the circuit breaker when it is automatically tripped on a fault current. This disadvantage was overcome by providing a transparent portion, such as a window glass, in the housing so that the maintenance man could readily observe the position of the cooperating contacts. However, this solution to one problem created a second problem and turned out to be unsatisfactory. That is, the window glass after several interruptions by the circuit breaker becomes foggy due M 2,805,294 Ce Patented Sept. 3, 1957 to are interruption and hence, the operator can no longer see the position of the contacts.

Still other prior art arrangements in order to overcome the noted disadvantages have been the provision of an indicating plunger arrangement associated with each contact arm of the circuit breaker as, for example, the type of arrangement shown and described in copending application Serial No. 467,686, filed November 9, 1954. Although this arrangement can be used in some installations, it does not have universal application since it does not provide sufiiciently positive indication that the circuit is tie-energized. That is, in case the indicating plunger fails, there may be a fales indication of the condition of the circuit.

My instant invention is directed to a means which provides a positive and foolproof indication to the maintenance man that the circuit on which he is working is completely de-energized.

My invention provides a mounting block for a multipole circuit breaker wherein the mounting block has a first set of spaced electrical terminals and a second set of spaced holding means wherein the circuit breaker is selectively positioned in either the electrical terminal means or the holding means of the mounting block. When the circuit breaker is removably connected to the electrical terminal means and the circuit breaker handle is in the closed position, the circuit will be energized.

If the maintenance man desires to work on the electrical line, he manually opens the circuit breaker and then selectively positions it in the holding means of the mounting block. Thus, there is a visual and positive indication that the circuit is completely de-energized even though the contacts may have welded together.

In addition to the above noted novel features of my instant invention, I have also provided an interlock arrangement between the circuit breaker and the mounting block on which it is to be mounted. With this interlock arrangement, the removal of the circuit breaker from the terminals of the mounting block will automatically trip open all three phases of the circuit breaker immediately prior to the electrical disengagement between the termi nals of the circuit breaker and those on the mounting block.

The interlock is a spring actuated plunger acting on the tripper bar to trip the circuit breaker upon its removal from the mounting block so that the circuit breaker is tripped and its contact opened before the separate connectors between the circuit breaker and the terminals of the mounting block are disengaged. Thus, in the event that the operator fails to mechanically open the breaker prior to an attempted removal of the circuit breaker from the mounting block, automatic interlock means will pre vent any damage to either the operator, the terminals, or the circuit protective means.

The interlock of the circuit breaker is operative to trip the circuit breaker whenever attempt is made to remove it from the mounting block. That is, as above noted, the primary function of the interlock will be to insure that all three poles of the circuit breaker are opened prior to the time that the circuit breaker is removed from its energized position on the mounting block to thereby prevent injury to personnel and equipment. However, the interlock also performs the function when the circuit breaker is moved from the dead position to the energized position on the mounting block. That is, while the circuit breaker is in the dead position, it would be dangerous if, while in this position, the personnel had moved the operating handle from the 005 to the on position since an attempted replacement of the circuit breaker to the energized position while the circuit breaker is closed could also result in injury to personnel and the equipment. However, with my novel interlock, the circuit breaker is automatically opened as soon as an attempt is made to remove it from either dead or energized position on the mounting block.

In addition to the selective positioning and the interlock features noted above, my novel mounting block enables and facilitates the complete wiring of the device without the circuit interrupter being in place. Thus, when the mounting blocks are mounted in an enclosure it can be completely wired when the circuit interrupters are removed, thereby permitting considerable accessibility within the enclosure for wiring purposes. Since all the permanent wire connections are made to the energized holding means or terminals of the mounting block, the circuit interrupter can be provided with disconnect contacts to facilitate it being selectively positioned on the mounting block.

Accordingly, a primary object of my invention is to provide a mounting block on which a circuit breaker can be selectively positioned to either an energizing position for the circuit or a dead position.

Another object of my invention is to provide a simple structural arrangement for the selective mounting of a circuit breaker wherein a plurality of holding means and a plurality of terminal connectors of'similar spacing and number to the terminals of the circuit breaker can removably receive the circuit breaker depending on whether or not the circuit is to be energized or de-energized.

Another object of my invention is to provide a novel interlock arrangement between the circuit breaker and its mounting block wherein the circuit breaker is automatically tripped when it is removed from the energized position on the mounting block.

A still further object of my invention is to provide a circuit breaker which can be selectively positioned in either an energized or dead position on the mounting block wherein the circuit breaker is provided with interlock means so that an attempted removal of the breaker from the energized position will automatically trip open the circuit breaker in the event that the operator has failed to mechanically perform this function.

Still another object is to provide an interlock between the circuit breaker and mounting block wherein an attempted removal of the circuit breaker from either the energized position or dead position on the mounting'block will altomatically trip open all three poles of the circuit breaker to thereby prevent any possible injury to personnel or equipment.

A further object of my invention is to provide a mounting block having means to selectively position a circuit interrupter wherein the device can be completely wired while the circuit interrupter is removed from the block.

These and other objects of my invention will be apparent from the following description when taken in connection with the drawings in which:

Figure 1 is a perspective view of the mounting block of my invention containing both the electrical terminals and the holding means.

Figure 1a is a cross-sectional view of the circuit breaker and mounting block of Figure 1 and illustrates the interlock between the circuit breaker and the mounting block. This figure illustrates the manner in which the interlock maintains the breaker in the tripped position when the circuit breaker is removed from the mounting block.

Figure 2 is a cross-sectional view similar to the arrangement of Figure 1 illustrating the circuit breaker removably positioned in engagement with the electrical terminals.

Figure 2a is a cross-sectional view of the arrangement of Figure 2 and illustrates the interlock arrangement between the circuit breaker and mounting block. In this figure, the circuit breaker is plugged into the mounting block so that the interlock is defeated and does not prevent the closing of the circuit breaker.

Figure 3a is an end view of Figure 2 illustrating the circuit breaker when it is removably connected to the electrical terminals of the mounting block.

Figure 3b is an end view similar to 31; showing the selective positioning of the circuit breaker in the holding means of the mounting block.

The circuit protective device 10, which forms no part of my instant invention, is of any desired construction as, for example, the type of molded case circuit breaker shown in U. S. Patent 2,574,093. However, the multi-pole circuit breaker 10 is provided with male stud disconnecting means 11a, 11b, 11c and Ella, 11b and 110 associated respectively with each phase on the load and source side of the circuit breaker 10.

The mounting block 29 and mounting block 20 are provided, respectively, for the load and source side of the circuit breaker and are of substantially identical construction. Hence, identical numerals are used to identify similar components of mounting blocks 20 and 20.

The block 2i? is made of insulating material and has a plurality of recesses 21a, 21b and 210 to which the tulip type stationary electrical terminals and the solderless connectors 32 are secured. Each of the recesses 21 corresponds to a pole of the circuit breaker 1t and identical components are positioned in each of the recesses 21. Thus, for example, a tulip clip 23 is positioned within the opening 21.

The tulip clip 23 is comprised of a base section 24 which extends into and through conducting member 25. A securing bolt 26 passes through an opening 27, 28 of the mounting block 20 and engages by any desirable means as, for example, threaded engagement, the member 24 to rigidly secure it in place and maintain its electrical engagement with the conducting member 25'.

The tulip clip 23 is made up of a plurality of members 29 which are held in position by means of the spiral circular springs 30 and 31 as best seen in Figure 2. The disconnect arrangement comprised of the male studs 11 and the tulip clips 23 may be of the type shown in copending application Serial No. 476,334, filed December 20, 1954, wherein the male studs 11 are provided with a swelled portion so that the stud and tulip clip will be held in engagement even though the unit is subjected to severe blow-off forces. 7

The solderless connector 32 is secured to the mounting block 20 by means of the screw 33 which also enables an electrical connection between the member 32 and a conducting bar 25. That is, the tulip clip 23 and the solderless connector 32 are in series electrical engagement through the conductor 25.

The circuit to be protected by the circuit protective device 10 is connected to the solderless connectors 32 associated with the mounting block 20 and the source energizing the circuit is connected to the solderless connectors 32' associated with the mounting block 20.

The entire mounting block assembly, comprised of blocks 20 and Ztl can be wired on the load and source by connecting the appropriate wires to the solderless conductors 32, 32'. This can be achieved while the circuit interrupter it is removed from the mounting blocks 20, 20 to thereby facilitate the wiring operation and allow the circuit interrupter 10 to be readily removable and replaceable.

When it is desired to have the circuit energized, the circuit protective device 10 is positioned so that the male stud terminals 11 are in electrical engagement with the tulip clips 23, and hence, they are effectively connected to their respective solderless terminals 32. p

The circuit protective device is provided with a handle 14 which can manually move the contacts within the circuit breaker 10 to the on or off position and when the circuit breaker 10 automatically opens, the handle will be moved from the on to the tripped position.

When a maintenance man desires to work on the circuit protected by the circuit breaker, the circuit breaker handle is moved to the off position. However, as noted in the introduction, this does not give a positive '5 indication that the circuit is de-energized since it is possible that the contacts within the housing of the circuit breaker have Welded together. Therefore, it is essential to provide a positive means whereby the maintenance man will be assured that the circuit on which he is to work is completely de-energized.

To this end, I provide a plurality of alternate connecting means which take the form of openings 40 in the mounting block 20. The openings 40 are equal in number and space relationship to the male studs 11 of the circuit breaker 10. The openings 40 are not electrically connected to the circuit and furthermore are properly insulated from the circuit because of the insulating material which forms the mounting block 20. Thus, the maintenance personnel can remove the circuit breaker 10 from electrical engagement with the tulip clip terminals 23 and can isolate the circuit breaker 10 by placing the male studs 11 into the openings 40, as illustrated in Figure 321. Thus, since the terminals 11 of the circuit breaker are physically removed and insulated from the terminals 23 and the mounting blocks 20, the circuit which was previously protected by the circuit breaker is de-energized and there is positive visual indication to the maintenance man of this fact.

Thus, I have provided a novel arrangement wherein within a single mounting block, a circuit breaker 10 can have its male studs 11 selectively positioned in the electrically connected terminals 23 when it is desired to energize the circuit or in the non-electrical connecting holding means 4% when it is desired that the circuit not be energized.

In the foregoing, it has been assumed that the operator has mechanically operated the handle 14 of the circuit breaker to the off position prior to the removal of the circuit breaker 10 from the energized terminals 23 of the mounting block 20 and also prior to the time that an attempted electrical engagement is made between the terminals of the circuit breaker 10 and the energized terminals 23 of the mounting block 20. Thus, unless this procedure is followed, damage to the personnel and equipment may very well result.

In order to eliminate the possibility of damage by failure of the operator to open the breaker prior to the time it is removed from the energized position or placed into the energized position, I have provided an automatic interlock wherein the circuit breaker 10 is tripped immediately prior to its disengagement from the energized terminals or immediately prior to its removal from the non-electrical connecting holding means 40.

Figures la and 2a illustrate my novel interlock means wherein Figure la shows the manner in which the interlock 50 trips the circuit breaker when the circuit breaker it) is removed from the mounted position illustrated in Figures 2, 2a and 3a to its un-mounted position illustrated in Figure 1.

Although I have shown in the illustration only the cross-section of the connection with the energized terminals 23, it will be apparent to those skilled in the art that the arrangement illustrated applies equally well when the circuit breaker is removed from the un-energized openings 49.

The interlock means 50 is comprised of a pin 51 which is slidably mounted in the opening 52 of the molding of the circuit breaker 10. The pin 51 is provided with a first ledge 53 and a second ledge 53 located, respectively, above and below an opening 55 in the tripper bar 54.

Biasing springs 56 are secured at their lower end to the molding of the circuit breaker 10 and at their upper end to the ledge 53' of the pin 51. The biasing springs 56 are in tension as seen in Figure 2a, and hence, tends to maintain the interlock pin 51 in its lowermost position as seen in Figure 1a. Since the upper portion of the pin 51 extends through the opening 55 of the tripper bar 6 54 which, in turn, is pivoted at fixed pivot point 57, the ledge 53 will rotate the tripper bar 54 in a counterlockwise direction when the biasing springs 56 are permitted to urge the pin 51 downwardly.

As is well known in the circuit breaker art, the cradle latch 58 will then be disengaged from the tripper bar latch 59, and hence, the circuit breaker will be tripped and can not be reset in this position. However, when the circuit breaker is placed on the mounting block 20, the lower edge of the interlock pin 51 will engage the upper surface of the mounting block 20 thereby urging it upwardly against the bias of the springs 56. This will remove the eldge 53 from engagement with the upper surface of the tripper bar 51 so that the tripper bar due to its ledge 53 will now be rotated back to the position indicated in Figure 2a so that it can be reset, that is, engagement of the latch surfaces 58-59.

When the operator starts to remove the circuit breaker from engagement with the terminals or openings in the mounting block 20, the biasing springs 56 will urge the interlock pin 51 downwardly thereby bringing its ledge 53 into mechanical engagement with the common tripper bar 54 to rotate same and thereby trip the breaker.

It will be noted that this occurs prior to the complete electrical disengagement of the terminal 11 of the circuit breaker 10 and the tulip clips 23 of the mounting block 20. Thus, complete safety to the personnel and equipment is insured when the circuit breaker is removed from its energized position by insuring that the circuit breaker is in the fully open position prior to disengagement from the mounting terminals.

In like manner, the interlock means 50 functions to trip the breaker when it is removed from its dead position so that when it is repositioned with the energized terminals 23, it will be in the tripped position and will offer complete safety to both operator and equipment.

In many installations, it is desirable to place both the mounting blocks 20 and 20' and the circuit breaker 10 within an enclosure 41 as seen in Figure 2. A sheet of insulating material 43 is placed on the bottom of the enclosure 41 and the mounting blocks 2020' are secured to the enclosure 41 by means of bolts passing through openings 42. The enclosure 41 may be provided with a cover having a handle which engages the handle 14 as shown and described in copending application Serial No. 421,753, filed April 8, 1954.

Thus, with this arrangement, if the circuit is energized and the maintenance man wishes to have a positive visual indication that the circuit is de-energized, he will follow the following procedure: Operate the enclosure handle so that the operating handle 14 of the circuit breaker 10 is moved from the on to the off position. He can then open the cover of the enclosure 41.

He would then physically remove the circuit breaker so that its male studs 11 are no longer in electrical engagement with the tulip clips 23. The circuit breaker would merely be shifted over so that the male studs 11 are now positioned in the openings 40, as illustrated in Figure 3b, which is the dead position of the circuit breaker. An enclosure cover door can then be reclosed and it will now be safe for maintenance personnel to work on the de-energized line.

In the foregoing, I have described my invention only in connection with preferred embodiments thereof. Many variations and modifications of the principles of my invention within the scope of the description herein are obvious. Accordingly, I prefer to be bound not by the specific disclosure herein but only by the appending claims.

I claim:

1. A mounting means for a multi-phase circuit interrupter being comprised of a terminal block containing a first and second plurality of holding means; said first plurality of holding means being constructed to be electrically connected to a circuit protected by said circuit interrupter; said second series of holding means containedlwithin said insulating mounting block being spaced from said first plurality of holding means; said circuit interrupter having terminal means corresponding in number to the number of said first holding means and also to the number of said second holding means; said circuit interrupter terminals, said first holding means, and said second holding means all being spaced in equal distance from each other, respectively; said circuit interrupter having terminals selectively positioned in said first and second plurality of holding means.

2. Mounting means for a multi-pole circuit breaker being comprised of a first mounting block for the load end of said circuit breaker and a second mounting block for said source end of said circuit breaker; said first and second mounting blocks having substantially identical construction; said mounting blocks being comprised of insulating material containing a plurality of spaced electrical terminal means corresponding in space and number to terminal means of said circuit breaker; said mounting blocks also containing a plurality of spaced non-electrical holding means corresponding in space and number to terminal means of said circuit breaker; said circuit breaker being selectively positioned in said electrical terminal means and said non-electrical holding means.

3. Mounting means for a multi-pole circuit breaker being comprised of a first mounting block for the load end or" said circuit breaker and a second mounting block for said source end of said circuit breaker; said first and second mounting blocks having substantially identical construction; said mounting blocks being comprised of insulating material containing a plurality of spaced electrical terminal means corresponding in space and number to terminal means of said circuit breaker; said mounting blocks also containing a plurality of spaced non-electrical holding means corresponding in space and number to terminal means of said circuit breaker; said circuit breaker being selectively positioned in said electrical terminal means and said non-electrical holding means; said circuit breaker operative to complete the electrical circuit between said first mounting biock and said second mounting block when said terminals are removably connected to said electrical terminal means; said circuit breaker being operative to insure de-energization of the circuit between said first mounting block and said second mounting block when said circuit breaker is removably connected to said non-electrical holding means.

4. A circuit interrupter terminal mounting block being comprised of insulating material having means to connect three spaced electrical terminals; each of said terminals being comprised of a solderless connector and a tulip clip connector; complete electric Wiring of said mounting block being completed by connecting load and source Wires to said 'solderless connectors; each of said terminals corresponding to a male stud connected; means on'the circuit interrupter which in turn is associated with each i 8 phase of the circuit interrupter; each of said tulip clip connectors adapted to removably receive said male stud terminals of said circuit interrupter; said mounting block having holding means corresponding in number and space relation to' said male stud terminals of said circuit interrupter; said circuit interrupter being selectively positioned in Said tulip clip connectors and said holding means to thereby selectively energize or de-energize the circuit being protected by said circuit interrupter.

5. A mounting block for removably connecting a circuit breaker to an electrical line; said mounting block being comprised of a holding and connecting terminal constructed to removably receive a terminal of said circuit breaker; said mounting block also having a holding means removed from said holding and connecting terminal; said terminal of said circuit breaker being selectively positioned in said holding and connecting terminal and said holding means; said circuit breaker having an interlock means to automatically trip said circuit breaker when said breaker is removed from either said holding connecting terminals or said holding means.

6. A mounting means for a multi-phase circuit interrupter being comprised of a terminal block containing a first and second plurality of holding means; said first plurality of holding means being constructed to be electrically connected to a circuit protected by said circuit interrupter; said second series of holding means contained Within said insulating mounting block being spaced from said first plurality of holding means; said circuit interrupter having terminals selectively positioned in said first and second plurality of holding means; said circuit interrupter having an interlock means to trip said circuit interrupter when said interrupter is removed from either said first or said second plurality of holding means.

7. A circuit breaker to be selectively positioned on a mounting block; said circuit breaker having an energized position and a non-energized position when reset to said mounting block; said circuit breaker being provided with an interlock unit; said interlock unit operatively connected to trip said circuit breaker when said circuit breaker is being removed from either said energized or de-energized position; said interlock means being comprised of a biased member having a first and second position; said biased member moved from said first to said second position when said circuit breaker is being removed from said mounting block to thereby effect tripping operation of said circuit breaker.

References Cited in the file of this patent UNITED STATES PATENTS 1,484,468 Brothers Feb. 19, 1924 1,869,936 Griswold Aug. 2, 1932 2,128,149 Linde Aug. 23, 1938 2,273,002 Mahoney Feb. 10, 1942 2,608,626 Morgan Aug. 26, 1952 

